In order to improve fuel efficiency or reduce exhaust emission, some cars having an engine such as an internal combustion engine include what is called an idling-stop or economy-running function, in which an engine is automatically stopped while a vehicle stops and a driver operates a brake pedal, and the vehicle is automatically re-started, for example, by a driver's operation for re-start such as decrease in an amount of operation of a brake pedal to zero.
In a vehicle including the idling-stop or economy-running function, due to drive of a starter in re-starting the engine after it is stopped, a voltage of a battery for supplying electric power to the starter may lower. As the voltage of the battery lowers, a memory in an ECU (Electronic Control Unit) may be reset.
In consideration of such facts, Japanese Patent Laying-Open No. 2010-24906 (PTL 1) discloses permission of idling-stop in a case where a lowest voltage of a battery at the time when an internal combustion engine is automatically started is expected to be equal to or higher than a threshold voltage.